'\" te
.\"  Copyright (c) 2003, Sun Microsystems, Inc.,  All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
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.TH LDI_READ 9F "Jun 3, 2003"
.SH NAME
ldi_read, ldi_write \- Read and write from a device
.SH SYNOPSIS
.LP
.nf
#include <sys/sunldi.h>

\fB\fR\fBint\fR ldi_read(\fBldi_handle_t\fR \fIlh\fR, \fBstruct uio *\fR\fIuiop\fR, \fBcred_t *\fR\fIcr\fR);
.fi

.LP
.nf
\fBint\fR \fB ldi_write\fR(\fBldi_handle_t\fR \fIlh\fR, \fBstruct uio *\fR\fIuiop\fR, \fBcred_t *\fR\fIcr\fR);
.fi

.SH PARAMETERS
.sp
.ne 2
.na
\fB\fIlh\fR \fR
.ad
.RS 9n
Layered handle.
.RE

.sp
.ne 2
.na
\fB\fIcr\fR \fR
.ad
.RS 9n
Pointer to a credential structure used to open a device.
.RE

.sp
.ne 2
.na
\fB\fIuiop\fR \fR
.ad
.RS 9n
Pointer to the \fBuio(9S)\fR structure. \fBuio(9S)\fR specifies  the location
of the read or write data.  (Either userland or kernel.)
.RE

.SH DESCRIPTION
.sp
.LP
The \fBldi_read()\fR function passes a read request to the device entry point
for the device specified by the layered handle. This operation is supported
for  block,  character, and streams devices.
.sp
.LP
The \fBldi_write()\fR function passes a write request to the device entry
point for a device specified by the layered handle. This operation is supported
for block,  character, and streams devices.
.SH RETURN VALUES
.sp
.LP
The \fBldi_read()\fR and \fBldi_write()\fR functions return \fB0\fR upon
success. If  a  failure occurs before the request is passed to the device, the
possible return values are shown below. Otherwise any other error number may be
returned by the device.
.sp
.ne 2
.na
\fBEINVAL\fR
.ad
.RS 11n
Invalid input parameters.
.RE

.sp
.ne 2
.na
\fBENOTSUP\fR
.ad
.RS 11n
Operation is not supported for this device.
.RE

.SH CONTEXT
.sp
.LP
These functions may be called from user or kernel context.
